1. Field of the Invention
The present invention relates to an electrophotographic type image forming apparatus and various cartridges which are attached to and detached from the apparatus. More particularly, it relates to a toner cartridge for housing toner, a process cartridge including a process portion, e.g. a developing apparatus or the like, an imaging cartridge including a toner cartridge and a process cartridge therein, and an image forming apparatus to which the above cartridges are attachable.
2. Description of the Related Art
Conventionally, in an electrophotographic type image forming apparatus, a developing apparatus installed therein develops an electrostatic latent image formed on an image carrier with toner and an image is formed thereby. There has occasionally been used an image forming apparatus of which toner housing portion and process portion including a developing apparatus portion are provided as separate units. The toner housing portion and the process portion of such a type image forming apparatus are separately attached to and detached from the main body. Generally, when both of them are attached to a main body of the apparatus and it is in an image-formation-possible state, toner is carried via a toner carrying tube which connects the toner housing portion and the process portion.
When the toner housing portion or the process portion is removed, it is required to prevent toner from dropping out inside the apparatus. Therefore, there has generally been devised a method that a toner carrying tube or the like for connecting units is placed aside or closed. On the other hand, Japanese Unexamined Patent Publication No. 2000-98713 discloses an image forming apparatus of which toner carrying tube is divided at its halfway. According to the Publication, both separated ends of the tube are connected to units, respectively. The tube is connected and disconnected along attachment and detachment of the units. The Publication further discloses an image forming apparatus equipped with a shutter at a connecting portion of a toner carrying tube, wherein the shutter opens and closes along with attachment and detachment of units.
Japanese Unexamined Patent Publication No. 07-152239 discloses an image forming apparatus in which a slide shutter is arranged on a bottom face of a toner cartridge. According to the Publication, a toner cartridge and a toner hopper are engaged with a locking member. Lock with the locking member is unlocked by closing the slide shutter. The mechanism allows a user to detach the toner cartridge when the slide shutter is closed.
However, the above-mentioned conventional image forming apparatuses had the following problems. As to the image forming apparatus directed to the Publication No. 2000-98713, the shutter is opened and closed along attachment and detachment of the units, so the shutter is half-opened in the middle of attachment and detachment operations. Therefore, in the case a user stops attachment or detachment operation in the middle and tries it again from the beginning or in the case a user cannot carry out attachment and detachment operation smoothly, toner can possibly run out from the half-opened shutter.
Furthermore, the image forming apparatus directed to the Publication No. 07-152239 cannot carry out image formation if a user forgets to open the slide shutter after a toner cartridge is attached. Furthermore, since no shutter is provided at its toner hopper side, toner can possibly scatter in the middle of attachment and detachment operation. That is, if a user wishes to keep his/her hands and surrounding clean from toner when attaching and detaching a unit of those conventional apparatus, careful and smooth attachment and detachment operation is demanded. However, proper operation was not easy for a user who rarely carries out the operation.